Soundproofing a pitched roof ! Any tips/ideas ?

[Rob Flinn]

My studio partner & I are taking on a new live room, which is roughly as follows:

7.5m x 5m Stone walls, concrete floor

The roof has a double apex, the highest being 6m the lower being 4m. The roof is done with a standard tin industrial roofing material.

The other day I set our drum kit up & had a play (sounded great despite my playing) but obviously could be heard outside, mainly through the roof. We therefore want to acoustically lag/soundproof the roof, whilst maintaining the angles/apexes etc because the room sounds good because it is not a rectangular box.

Can anyone suggest any products/methods for us to use. I have several acoustics books, but because they are Yank books the brands are not ones that are available in the UK. Also we do not have an unlimited budget so anyone suggesting us to get toyoshima to design it won't be taken too seriously !!

In reality I have some ideas in mind but thought it would be useful to see if anyone else could bring anything to the table ?

 

[SSLtech]

ugh...

Air-to-diaphragm-to-air transfer. Five-second knee-jerk reaction post follows:

You have to either add an airtight isolation boundary (pain in the balls) or add LOTS of mass to the diaphragm (not going to happen).

Second-boundary seems like the only realistic option. That means a "roof within a roof" inside the existing boundary, and it has to be airtight. Where air can pass, so will sound.

Dassit.

Keith

 

[Guest]

The US books mention Owens Conning 703?? Replacement in the UK is rockwool RW5 or RW3 if memory serves me right
Get it from Travis Perkins but haggle for discount you can get it 50% less if you have a mate who is a regular customer sort of thing?
Or am I barking up the wrong tree?

Start here..
http://www.soundonsound.com/forum/showflat.php?Cat=&Number=54398&page=0&view=collapsed&sb=5&o=&fpart=1#54398

For acoustic treatment
http://www.samplecraze.com/tutorial.php?xTutorialID=28

 

[burdij]

No you are not barking up the wrong tree. Check out the discussions about rockwool and Owens 703 on this site:

http://www.johnlsayers.com

In fact, I think there are a couple threads about studios with this particular configuration. Look in the forums.

Also, this site has good info, calculators and charts showing characteristics of various absorption materials:

http://www.atsacoustics.com/

Probably won't be able to get materials from them, though, since they are in Illinois.

 

[Sleeper]

Hi Rob, I have to go with Kieth on this, if you want to keep sound from getting out you have to put in another ceiling AND make it airtight AND give it as much mass as possible AND decouple it from the roof structure.
I guess the real question here isn't so much about the tin roof, but what's holding it up?
Steel Joists or wood?
if it's wood there's a z bracket, kind of a zigzag piece of metal that will decouple sheetrock from your joists. very effective.
Steel joists and beams, I'm not sure where, but I have seen some clips that will let you clip substructure on to the beams without drilling them.


Classic American style "drop ceiling" tiles and t-bars isn't super effective, but it's really quick and easy and with enough fiberglass insulation or rockwool you'll make a dent. maybe a big enough dent?

If you aren't going to connect directly to the existing ceiling take the sub- ceiling out of parallel with the tin roof.

Kelly

 

[Bryson]

What if there was a way, with speakers on the roof, to inject into the air a signal that's out of phase with the leakage.
Kinda like noise canceling headphones.

I know....silly thought.

 

[Rob Flinn]

Thanks for the tips so far.

Keith & Kelly I hear you with the sub roof thing.

The roofing joists are wood, but are substantial, since it's a farm building that is about maybe 150 years old.

With regards to doing the sub ceiling, it's a difficult call. The easiest solution seems to be to pack between the joists with dense fibreglass & then nail plasterboard over it. Although It's difficult to know in advance whether this would reduce the spill to an acceptable level. It's difficult to know how far to go as there aren't any immediate neighbours for 100m, but at the same time it doesn't pay to upset the landlord if we have a metal drummer in there ;-). Also we don't have an umlimited budget .

 

[SSLtech]

[quote author="Bryson"]What if there was a way, with speakers on the roof, to inject into the air a signal that's out of phase with the leakage.
Kinda like noise canceling headphones.

I know....silly thought.[/quote]
If you like the sound in the room, that method DESTROYS it.

..It also does very LITTLE to help sound leaking through the roof... it may possibly appear louder outside than in, using that approach!

You have to understand the mechanism first, then look at how to make the mechanism less efficient... hence I posted:
[quote author="SSLtech"]Air-to-diaphragm-to-air transfer.[/quote]

Either make the diaphragm less efficient (mass) or prevent the air from meeting it (practically awkward to build a self-sustaining vacuum) or build a sealed, mass-heavy boundary to quieten down the air that does meet the roof...

Surface treatments will soften or damp the diaphragm, but do little to dent the actual transmission through the roof... but they will do a wonderful job of ******* up the reflections in the room... Sadly, if Rob enjoys the sound of the room as it is (and I presume that he does) then surface treatment is a worthless approach.

Keith

 

[Sleeper]

http://www.acousticalsurfaces.com/rsic_clips/risc_clips.htm?d=46
here's a version of the z-channel idea.

the stuff here is all pretty interesting, but they are asking a seriously premium price for being specifically "sound control" products.
like auralex sells it for about 7usd a stick:evil:
http://truesoundcontrol.com/products/RC824.html?gclid=CNzUkd2h640CFSSQYAodvCKmvA

They use it for walls and ceilings in cheap apartments and hotels.
go to the biggest baddest commercial sheetrock/gypsum board supplier you can find and they'll have it for more like 2dollars (and that's without the 24piece discounts)

Kelly

oh yeah, I've generally liked they rooms I used RC in/on (i'll call it by it's proper name now!) it has a springy sound

 

[TomWaterman]

With that kind of roof and a tracking room, isn't the sound of rain/hail/bird **** hitting the roof as much of a disruption to your environment as the leaking sound to the farmer/landlord?

I agree the only way is to seal it off.

Do you have horizontal beams at a lower height to the A-frame or can you access almost max height?

-T